Home Battery Backup in Canada: Sizing, Cost and When It's Worth It

A home battery stores electricity and supplies it when the grid goes down. In Canada, most people buy one for backup during outages from ice storms, windstorms and summer thunderstorms. Paired with solar, a battery can also store daytime power for use at night.

For most homes, a battery is a backup and resilience purchase. It rarely pays for itself on bill savings alone. It can be worth it if outages are common where you live, if you rely on a sump pump or medical equipment, or if rebates cover a large share of the cost.

How home battery backup works

A battery connects to your electrical panel through an inverter. When the grid fails, a transfer switch isolates your home and the battery takes over, usually within a fraction of a second. Most systems back up a separate panel of essential circuits. Whole-home backup is possible but costs more and needs more storage.

Battery size has two numbers. Capacity, in kWh, is how much energy it stores. Power, in kW, is how much it can deliver at once. A battery with plenty of kWh but low kW may not be able to start a well pump or central air conditioner.

How to size a home battery in kWh

List the loads you need during an outage, estimate how many hours each runs per day, and add them up. The table shows typical figures. Your appliances will differ, so check the labels or use our appliance calculator.

Essential loads like these often total 6 to 15 kWh per day. A 10 to 15 kWh battery typically covers essentials for about a day, longer if you are careful. If you have solar, it can recharge the battery on sunny days, though winter output is low. See how solar performs in winter.

Why electric heat changes the math

Heating is roughly 60% of the energy a typical Canadian home uses. A heat pump or electric baseboard system can use 30 to 100 kWh or more on a cold winter day. Backing that up for a long outage would need several batteries. Homes with electric heat usually plan for a few hours of heating, a backup wood or gas fireplace, or a generator. Our battery backup calculator estimates runtime for your loads.

What a home battery costs in Canada

Installed prices vary with brand, capacity, whether you need a new subpanel and how much electrical work is involved. As a rough guide, a single battery of about 10 to 15 kWh typically runs in the range of $12,000 to $20,000 installed before rebates. Additional batteries on the same system usually cost less each, since the inverter and wiring are shared.

Rebates for home batteries

In Ontario, the Home Renovation Savings Program offers up to $5,000 for a home battery, or up to $10,000 when combined with rooftop solar. That can take a large share off the cost. Other provinces and utilities may offer support from time to time, so check your provincial rebate page for current programs.

When a home battery is worth it

• You live in an area with frequent or long outages.
• You rely on a sump pump, well pump or medical equipment.
• You already have, or are adding, solar and your export credit is low, so storing daytime power has real value.
• You are in Ontario and on a time-of-use or ultra-low overnight plan, where stored power can shift some use away from peak hours.
• A rebate covers a meaningful share of the cost.

It is likely not worth it if outages are rare and short, your export credit is close to retail, and you have no rebate. A small generator may cover occasional outages for far less. If you are adding solar at the same time, read our solar payback guide and how to compare solar quotes first.